Osteoarthritis involves the wear of the cartilage (soft, white coating over bone ends where two or more bones come together) in joints. Once the cartilage is entirely worn, then bone on the two sides of a joint come together and there is bone-on-bone contact. Osteoarthritis in the wrist most commonly affects the joint at the base of the thumb (the thumb carpal-metacarpal joint or CMC joint) where it connects to the wrist.

Thumb CMC joint osteoarthritis presents with localized pain in this joint. The joint is located deep to the muscles at the base of the palm on the thumb side of the hand. This pain may sometimes be confused with carpal tunnel syndrome. Careful history and examination will help distinguish thumb CMC joint osteoarthritis from carpal tunnel syndrome. There is point tenderness over the thumb CMC joint with osteoarthritis. There is also pain when compression force is applied to the thumb thereby loading the thumb CMC joint. There may be visible enlargement of the thumb CMC joint due to swelling and bone spurs. CMC joint osteoarthritis is not associated with finger numbness or tingling since there is no involvement of median nerve which is affected in carpal tunnel syndrome.

The treatment of thumb CMC joint osteoarthritis includes the use of splints to protect and immobilize the joint. A person should refrain from forceful use of the hand. NSAID medications can be used. Occasional local steroid injections may provide temporary relief. Local heat can also provide temporary relief.

A variety of surgeries can be done for extremely painful cases that are inadequately treated with nonsurgical measures. It is possible to fuse the thumb CMC joint. This is a way to surgically join the bones across the joint in order to eliminate motion at the worn joint. It is also possible to remove the bone called the trapezium located at the base of the thumb. A rolled up piece of tendon can be inserted in its place. This is called an "anchovy" procedure. There are also trapezium prostheses that can be used to replace the trapezium bone.

QwiTM Gloves and the Qwi Solution are not beneficial for the prevention or treatment of thumb CMC joint osteoarthritis.

X-ray of a normal left hand. The black arrow points toward a normal thumb CMC joint with no osteoarthritis. Notice the smooth borders around the bones and also the space between the bones. This space is occupied by normal articular cartilage.

X-ray a hand with severe osteoarthritis involving the thumb CMC joint as indicated by the black arrow. Notice how there is no space between the bones because all of the articular cartilage has been worn away. There is also a white stripe of bone on either side of the worn joint. This is called subchondral sclerosis and represents hard, dense bone that develops beneath joints whose cartilage has worn away thereby transferring more stress to the underlying bone. The joint margins are no longer smooth. Instead, there are bony prominences at the joint margins. These are called bone spurs or osteophytes.